gcc/ada/s-widenu.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                      S Y S T E M . W I D _ E N U M                       --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2000 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This package contains the routine used for Enumeration_Type'Width
  36
  37 package System.Wid_Enum is
  38 pragma Pure (Wid_Enum);
  39
  40    function Width_Enumeration_8
  41      (Names   : String;
  42       Indexes : System.Address;
  43       Lo, Hi  : Natural)
  44       return    Natural;
  45    --  Used to compute Enum'Width where Enum is some enumeration subtype
  46    --  other than those defined in package Standard. Names is a string with
  47    --  a lower bound of 1 containing the characters of all the enumeration
  48    --  literals concatenated together in sequence. Indexes is the address
  49    --  of an array of type array (0 .. N) of Natural_8, where N is the
  50    --  number of enumeration literals in the type. The Indexes values are
  51    --  the starting subscript of each enumeration literal, indexed by Pos
  52    --  values, with an extra entry at the end containing Names'Length + 1.
  53    --  The reason that Indexes is passed by address is that the actual type
  54    --  is created on the fly by the expander.
  55    --
  56    --  Lo and Hi are the Pos values of the lower and upper bounds of the
  57    --  subtype. The result is the value of Width, i.e. the maximum value
  58    --  of the length of any enumeration literal in the given range.
  59
  60    function Width_Enumeration_16
  61      (Names   : String;
  62       Indexes : System.Address;
  63       Lo, Hi  : Natural)
  64       return    Natural;
  65    --  Identical to Width_Enumeration_8 except that it handles types
  66    --  using array (0 .. Num) of Natural_16 for the Indexes table.
  67
  68    function Width_Enumeration_32
  69      (Names   : String;
  70       Indexes : System.Address;
  71       Lo, Hi  : Natural)
  72       return    Natural;
  73    --  Identical to Width_Enumeration_8 except that it handles types
  74    --  using array (0 .. Num) of Natural_32 for the Indexes table.
  75
  76 end System.Wid_Enum;